docs: def on_confirmation(self, frame):
          """Invoked by pika when RabbitMQ responds to a Basic.Publish RPC
          command, passing in either a Basic.Ack or Basic.Nack frame with
          the delivery tag of the message that was published. The delivery tag
          is an integer counter indicating the message number that was sent
          on the channel via Basic.Publish.
  
          :param pika.frame.Method frame: Basic.Ack or Basic.Nack frame
  
          """
          delivered = frame.method.NAME.split('.')[1].lower() == 'ack'
          self.logger.debug('Received publisher confirmation (Delivered: %s)',
                            delivered)
          if frame.method.multiple:
              for index in range(self.last_confirmation + 1,
                                 frame.method.delivery_tag):
                  self.confirm_delivery(index, delivered)
          self.confirm_delivery(frame.method.delivery_tag, delivered)
          self.last_confirmation = frame.method.delivery_tag